首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   5914篇
  免费   759篇
  国内免费   47篇
耳鼻咽喉   45篇
儿科学   143篇
妇产科学   149篇
基础医学   642篇
口腔科学   79篇
临床医学   605篇
内科学   1775篇
皮肤病学   303篇
神经病学   656篇
特种医学   142篇
外科学   477篇
综合类   5篇
预防医学   667篇
眼科学   35篇
药学   295篇
中国医学   6篇
肿瘤学   696篇
  2024年   23篇
  2023年   124篇
  2022年   135篇
  2021年   251篇
  2020年   225篇
  2019年   188篇
  2018年   219篇
  2017年   199篇
  2016年   253篇
  2015年   287篇
  2014年   379篇
  2013年   463篇
  2012年   421篇
  2011年   403篇
  2010年   286篇
  2009年   361篇
  2008年   333篇
  2007年   312篇
  2006年   305篇
  2005年   247篇
  2004年   226篇
  2003年   218篇
  2002年   180篇
  2001年   77篇
  2000年   55篇
  1999年   60篇
  1998年   82篇
  1997年   46篇
  1996年   42篇
  1995年   43篇
  1994年   42篇
  1993年   22篇
  1992年   25篇
  1991年   29篇
  1990年   21篇
  1989年   15篇
  1988年   14篇
  1987年   19篇
  1986年   12篇
  1985年   17篇
  1984年   15篇
  1983年   6篇
  1982年   10篇
  1981年   7篇
  1980年   5篇
  1979年   4篇
  1978年   3篇
  1977年   2篇
  1975年   2篇
  1974年   3篇
排序方式: 共有6720条查询结果,搜索用时 15 毫秒
71.
Background: In the last few years, there has been increasing demand for aesthetic procedures to improve the effects of skin aging.

Aim: To evaluate the anti-aging efficacy, tolerability and skin changes induced by the topical products containing hyaluronic acid, N-acetyl glucosamine and gamma-amino butyric acid through instrumental techniques, clinical and subjective evaluation.

Patients/Method: Twenty female enrolled applied a day and night cream after applying a serum, once week applied a mask, for 2 months. A clinical assessment of smoothness, expression wrinkles, fine wrinkles and measurements of the parameters using Reveal Imager, X-Rite, Corneometer, Dermalab, Moisture Meter EpiD were taken at day 0, 15, 30 and 60 of study period. A final assessment questionnaire was submitted.

Results: The products were accepted by all the volunteers. The hydration (Corneometer: T0 49.17 vs T60 61.11, average variation 24.28%) (Moisture Meter EpiD: T0 45.73 vs T60 61.10, average variation 33.60%), elasticity (Dermalab: T0 56.06 vs T60 62.78, average variation 11.98%) and lightening of the skin (X-Rite: T0 60.23 vs T60 63.36, average variation 5.26%) improved. All changes were statistically significant (p < 0.05).

Conclusion: The efficacy of the topical products is confirmed by subjective, clinical and instrumental assessment. This should be a routine approach in dermatologic practice.  相似文献   

72.
Background: Recent introduction of direct antiviral agents (DAAs) has completely changed the scenario regarding hepatitis C virus (HCV) treatment. Certain countries’ economic health programs prioritize DAAs according to specific clinical features of HCV-infected patients. The aim of this study was to define epidemiological, demographic and clinical characteristics of HCV-infected patients in the Tuscany region of central Italy.

Methods: We enrolled HCV patients with chronic viral hepatitis who were referred to the outpatient services of 16 hospitals in Tuscany from 1 January 2015 to 31 December 2015. Case report forms contained patient information including main demographic data, blood chemistry data, viral hepatitis markers, instrumental evaluations (liver biopsy or transient elastometry, liver ultrasound), eligibility for DAAs, and liver transplantation or therapy already in progress.

Results: Of all patients considered, 2919 HCV patients were enrolled (mean age: 57.44?±?15.15; 54% males, 46% females). All routes of transmission were well represented (intravenous drug use in 20.7%; nosocomial/dental care in 20.6%; and coagulation factors/blood transfusions in 13.3%). Diabetes was the highest represented comorbidity (20.8%), followed by metabolic syndrome (15.5%) and ischemic heart disease (6.2%). The most prevalent HCV genotypes were 1b (47.4%) and 2 (16.5%). In the whole cohort of patients, 32.8% were cirrhotic (40 patients were listed for liver transplantation). Signs of portal hypertension were present mostly in the group older than 45 years (92.3%). Extrahepatic HCV-related diseases were present in 13.3% of cases (cryoglobulinemic syndrome in 58.3% and B-cell non-Hodgkin’s lymphoma in 10.5%).

Conclusions: Our study provides evidence of a high prevalence of epidemiological changes in HCV infection with a major prevalence of advanced liver disease, such as portal hypertension, in this elderly cohort of patients.  相似文献   

73.
Our group has previously found that in silico, mechanical anisotropy may be interrogated by exciting transversely isotropic materials with geometrically asymmetric acoustic radiation force excitations and then monitoring the associated induced displacements in the region of excitation. We now translate acoustic radiation force-based anisotropy assessment to human muscle in vivo and investigate its clinical relevance to monitoring muscle degeneration in Duchenne muscular dystrophy (DMD). Clinical anisotropy assessments were performed using Viscoelastic Response ultrasound, with a degree of anisotropy reflected by the ratios of Viscoelastic Response relative elasticity (RE) or relative viscosity (RV) measured with the asymmetric radiation force oriented parallel versus perpendicular to muscle fiber alignment. In vivo results from rectus femoris and gastrocnemius muscles of boys aged ~7.9–10.4 y indicate that RE and RV anisotropy ratios in rectus femoris muscles of boys with DMD were significantly higher than those of healthy control boys (RE: DMD?=?1.51 ± 0.87, control?=?0.99 ± 0.69, p?=?0.04, Wilcoxon rank sum test; RV: DMD?=?1.04 ± 0.71, control?=?0.74 ± 0.22, p?=?0.02). In the gastrocnemius muscle, only the RV anisotropy ratio was significantly higher in dystrophic than control patients (DMD?=?1.23 ± 0.35, control?=?0.88 ± 0.31, p?=?0.04). In the dystrophic rectus femoris muscle, the RE anisotropy ratio was inversely correlated (slope?=?–0.03/lbf, r?=?–0.43, p?=?0.07, Pearson correlation) with quantitative muscle testing functional output measures but was not correlated with quantitative muscle testing in the dystrophic gastrocnemius. These results suggest that Viscoelastic Response RE and RV measures reflect differences in mechanical anisotropy associated with functional impairment with dystrophic degeneration that are relevant to monitoring DMD clinically.  相似文献   
74.
75.
PURPOSE: To conduct a Fehring model‐based clinical validation of the defining characteristics of the nursing diagnosis of impaired physical mobility in a sample of 250 patients. METHOD: Cross‐sectional study. FINDINGS: Three of the 11 NANDA‐International defining characteristics assessed in this study were validated: limited range of motion, limited ability to perform gross motor skills, and difficulty turning. Although discomfort was not validated due to the rarity of occurrence, there was excellent interrater agreement as to its relevance (kappa coefficient). CONCLUSIONS: In this setting, three characteristics were validated. IMPLICATIONS FOR NURSING PRACTICE: Validation studies are important for advancing evidence‐based practice.  相似文献   
76.
77.
Aims: Nestin (a neuronal stem cell/progenitor cell marker of central nervous system development), vimentin (which is ubiquitously expressed in mesenchymal cells), and the glucocorticoid receptor (GR, which is involved in the immune response, cell proliferation, and apoptosis) have been shown to interact in embryonic and undifferentiated tissues in modulating cell proliferation. The aim of this study was to analyse nestin, vimentin and GR expression in tumour tissue (melanoma), and their association with clinicopathological variables, to evaluate any effect on tumour progression. Methods and results: Immunohistochemistry, double‐label immunofluorescence and confocal laser scanning microscopy were performed on biopsy specimens of cutaneous melanoma from 81 patients. Fisher’s and Pearson’s tests showed a correlation between nestin, vimentin and subcellular GR location (P = 0.008). Their concomitant expression also correlated with Clark level and thickness (P = 0.02 and P = 0.029, respectively). Kaplan–Meier analysis revealed a poorer outcome for stage III and IV patients with associated expression of nestin, vimentin and cytoplasmic GR in tumour tissue (P = 0.02). Conclusions: These results suggest the presence in melanoma of growth mechanisms involving nestin, vimentin, and GR, similarly to that occurring in embryonic and undifferentiated cells, and may help in understanding tumour biology to provide a molecular basis for clinical therapies.  相似文献   
78.
79.
80.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号